Photoluminescence of Phosphorous Doped SiC

Abstract:

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We report the results of a photoluminescence (PL) study of n-type phosphorus-doped SiC
epilayers. The PL spectra consist of a set of sharp lines that are interpreted as excitons bound to the
P donor with zero-phonon lines which have photon energies very close to the nitrogen-bound
excitons and followed by phonon assisted replicas.

Abstract: The photoluminescence (PL) of the UD-4 defect is observed in semi-insulating bulk 4H,
6H and 15R SiC. In 4H and 6H SiC the UD-4 defect consists of two families of no-phonon (NP) lines,
Ua and Ub, and in 15R SiC it consists of three families, Ua, Ub and U15R. The Ua family in 4H, 6H
and 15R all show similar temperature behavior with higher energy NP lines becomming observable at
higher temperatures. In the case of the Ub and U15R families, a luminescence line with lower energy
than the prominent luminescence line appears at higher temperatures. The polarization and Zeeman
measurements suggest that the defect has C3v symmetry.

Abstract: We report on the luminescence spectra related to Ti impurity in both 4H- and 6H-SiC
polytypes. The spectrum depends strongly on the polarization. They are two families of lines in 4H
and three in 6H. The main no-phonon line of each family is shown as a triplet and its phonon structure
contains both sharp and broad replicas. The higher energy family has also extra lines at high energy
appearing when the temperature increases. The spectra can be detected with excitation energy below
the excitonic bandgap and even with excitation energy below the spectrum itself. Time-resolved
photoluminescence reveals 0.1 ms long lifetime at low temperature.

Abstract: Photoluminescence (PL) spectroscopy has been used to characterize neutron-irradiated cubic silicon carbide crystals. The effects of thermal annealing (600-1100OC) on the PL bands have been studied. Several PL bands consisting of a sharp line and its phonon replicas have been observed in the 9-80 K temperature range. Certain of them like the D1 spectrum doublet with 1.975 eV and 1.977 eV zero-phonon lines (ZPL) at 9 K and the L2 spectrum with ZPL at 1.121 eV were reported previously for ion-implanted and electron irradiated 3C-SiC crystals, respectively. Besides, some new bands with ZPL at 2.027, 1.594, 0.989 and 0.844 eV and a broad band at 1.360 eV have been found. A correlation of PL and EPR spectra intensities of these neutron-irradiated and annealed cubic SiC crystals is briefly discussed.